Calendar correction mechanism for timepiece

ABSTRACT

A calendar display correction mechanism for a timepiece, comprising a manually operable and time-settable stem, a correction wheel adapted for being driven therefrom, a rotatable date calendar display dial, a rotatable day calendar display dial, first motion-transmitting means adapted for establishing a motion-transmitting relationship from said correction wheel to said date dial, second motion-transmitting means adapted for establishing a motion-transmitting relationship from said correction wheel through a day star wheel to said day dial, and mechanical switching means adapted for selective establishiment of either of said first or second motion-transmitting relationship responsive to the direction of rotation of said stem, said mechanism being characterized in that said correction wheel is mounted on said stem for performing a unitary rotation therewith and that said mechanical switching means and said first and second transmission means are united into one and the same member.

United States Patent 1 Miyasaka et al.

[ 1 May 15, 1973 [54] CALENDAR CORRECTION MECHANISM FOR TIMEPIECE [73] Assignee: Citizen Watch Company. Limited,-

Tokyo, Japan [22] Filed: Feb. 14, 1972 [21] Appl. No.: 225,962

[30] Foreign Application Priority Data 3,645,090 2/1972 Mochizuki et al ..58/58 Primary Examiner-George H. Miller, Jr. Attorney- Holman & Stern 71 ABSTRACT A calendar display correction mechanism for a timepiece, comprising a manually operable and time settable stem, a correction wheel adapted for being driven therefrom, a rotatable date calendar display dial, a rotatable'day calendar display dial, first motiontransmitting means adapted for establishing a motion transmitting relationship from said correction wheel to said date dial, second motion-transmitting means adapted for establishing a motion-transmitting relationship from said correction wheel through a day star wheel to said day dial, and mechanical switching means adapted for selective establishiment of either of said first or second motion-transmitting relationship responsive to the direction of rotation of said stem, said mechanism being characterized in that said correction wheel is mounted on said stern for performing a unitary rotation therewith and that said mechanical switching means and said first and second transmission means are united into one and the same member.

7 Claims, 7 Drawing Figures z: lllllllll v m PAIENTEUKAY {5191a SHEET1UF4 FIG. I

PATENTEUMAYI 5191s 3'', 732,687

SHEET 2 BF 4 CALENDAR CORRECTION MECHANISM FOR TIMEPIECE BACKGROUND OF THE INVENTION This invention relates to improvements in and relating to a calendar display correction mechanism for a timepiece with at least two series of calendar representations, such as those relating to calendar dates, calendar days, calendar months and the like.

As is very well known, calendar watches capable of displaying the day and date calendar are broadly sold on the world market. Almost all of these marketed watches are provided with a quick correction mechanism for date calendar display, while, for performing a day calendar display correction, the operator must turn the watch hands as in the case of a time-setting job.

Most recently, however, calendar watches having a day calendar display corrector have appeared on the market. A representative day calendar corrector operates in such a way that the winding stem is drawn out to set it at its correction service position where by tuming the stern in one direction, the date calendar display is corrected as desired and by turning it in the opposite direction, the day calendar display is corrected again as desired, thus providing a very convenience to the user of the watch.

It should be noted, however, that this kind of modern calendar display correction mechanism comprises two clutch wheels, a number of additional transmission wheels or massive idlers, which requires as a whole an appreciably increased space occupied by the correction mechanism within the highly crowded inside space of the watch, in addition to the thus caused increase in the number of constituent parts. Some of these requires a rather increased thickness of the part or a substantially increased occupying area thereof which invites necessarily an increase of the outline dimensions of the watch with an increased manufacturing cost and a complicated structure thereof.

BRIEF SUMMARY OF THE INVENTION It is the main object of the present invention to provide a calendar display correction mechanism devoid of the aforementioned conventional drawbacks by providing a highly simplified motion-transmitting means from the time-settable stem to the day-and-date star wheels cooperating with the respective dayand date calendar display dials.

For this purpose, as the first-main feature of the invention, a correction wheel is mounted directly on the stem for attaining a direct coupling therebetween. As the second main feature of the invention, a specially designed pawl assembly, the main substantial part thereof being arranged substantially and practically on a plane parallel to that including the pillar plate of the timepiece, for selective operational coupling with the either of the dayand date star wheels, practically without use of intermediate transmission gears.

BRIEF DESCRIPTION OF THE DRAWINGS These and further objects, features and advantages of the invention will become more apparent when read the following detailed description by reference to the accompanying drawings illustrative of substantially two preferred embodiments of the invention.

In the drawings:

FIG. 1 is a partial plan view of a substantial part of a watch movement which is fitted with a preferred first embodiment of the calendar display correction mechanism according to this invention.

FIG. 2 is a partial section of the mechanism substantially taken along a section line II-II shown in FIG. 1.

FIG. 3 is an enlarged section of the timepiece shown in FIG. 1, taken substantially along a section line l-l shown in FIG. 1. This figure is divided into two parts (A) and (B) which can be united together into a'sole figure by overlapping two separation broken lines X-X with each other. The calendar display correction mechanism is shown in its working position for performing a day calendar correction.

FIG. 4 is a similar view to a part of FIG. 1, illustrative, however, of the calendar correction mechanism which in in its selected position for performing a date correcting job.

FIG. 5 is a similar view to FIG. 4, wherein the mechanism is positioned for performing a day correction job.

FIG. 6 is a similar view to FIG. 1, illustrative, however, of a preferred second embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIGS. 1-4 of the drawings, a first embodiment of the invention will be described in detail.

In these figures, numeral 1 represents a conventional pillar plate of a timepiece movement, said plate being shown highly schematically and only partially and thus, various and conventional recesses, openings and the like mechanical depressions or projections have been omitted from the drawing for simplicity. Numeral 2 represents a conventional rotatable stem, preferably a winding and time-setting stem which has a serrated crown fixedly attached to said stern, yet not shown only for simplicity.

A setting lever 3 has its pivot shaft 3a which is mounted, as conventionally on a stem positioning plate 4 which is shown only schematically and partially. One end of the lever 3 is kept in engagement with a ring groove 2a (cf. FIG. 3) formed on said stem 2, and three separate projections 3b, 3c and 3d are formed on the lever 3 integrally therewith, and in proximity to the other end thereof. The first one 3b of these projections is shown more specifically in FIG. 2 in its section along a section line II -II shown in FIG. 1. Other projections 36 and 3d are formed in the similar way although not shown.

Substantial part of the positioning plate 4 rs so designed and arranged to extend in a parallel plane with pillar plate 1 and fixedly attached therewith by means of several set screws, not shown. This plate 4 is formed integrally by a punching press job with two separate positioner projections 4a and 4b extending in respective lateral directions relative to the main plate part of the member 4, for positioning the stem 2 relative to pillar plate 1 by embracing substantially a half peripheral sur face of the stem with a certain resilient pressure acting thereon. Further, the member 4 is formed integrally with a clutch lever 5 and a setting lever spring 6 as shown.

The setting lever 6 is formed integrally with an elongated and elastic arm 6a which is formed in turn with three successive recesses a, b and c in close proximity of the tip end of said arm. The projection 3d of setting lever 3 is kept in pressure contact with one of these recesses for positively positioning occasionally'selected one of three different axial positions of thestem 2 as conventionally.

Clutch lever 5 extends inwards along a substantial distance from the positioning plate 4, thus having a resiliency as conventionally, and is kept in engagement at its tip end 5a with a ring recess 7d formed on a correction wheel 7. The lever 5 is formed at its intermediate point between its both ends with a wavy part 5b which is adapted for engagement with either of said projections 3b or 30 on setting lever 3 for being differently positioned by movement of the latter.

As most clearly seen from FIG. 3, the correction wheel 7 comprises a first gear 7a which corresponds to the conventional winding pinion, a second gear 7b having correction teeth 7b and a third gear 7c which corresponds to the conventional clutch wheel, said ring groove 7d being formed between said second and third gears. The correction wheel 7 is further formed with an axially extending square bore 7e through which a square shaft part 20 of stem 2 passes slidably. Thus, it will be seen that the correction wheel can rotate in unison with the stem 2 and is slidable therealong.

Numeral 8 represents a conventional setting wheel which is rotatably mounted on a stationary shaft part la formed integral with pillar plate 1, as most clearly be seen from FIG. 3. Numeral 9 represents a conventional minute wheel which is kept always in gear meshing with said setting wheel 8.

In FIG. 3, numeral 10 represents only partially a conventional center bridge and 11 denotes partially a conventional barrel and train wheel bridge, said bridges 10 and 11 being rigidly supported by the pillar plate, although the supporting means have been omitted by virtue of its very popularity. Numeral 12 represents a conventional crown wheel which is kept in gear meshing with the regular winding wheel serving for barrel spring winding. In the case of an electronic timepiece, the crown whee] can naturally be dispensed with. The crown wheel 12 is rotatably mounted on a headed pivot pin 11a which is press-fit partially into the bridge 11. The pivot head, denoted 11a, has a substantial thickness and is arranged to occupy a position in close proximity to the stem 2 in such a way that it acts as an effective stop means for the latter against a possible disengagement of the stem from its embraced position by the positions 4a and 4b, should the stem be subjected to an occasional substantial lateral outside force as may be liable to be met in case of the barrel spring winding.

Numeral 13 represents a conventional date dial which is shaped into a ring having inner teeth 13a, the number of the latter corresponding naturally to those of dates of the odd calendar month. This dial 13 is rotatably mounted on the pillar plate 1, although the mounting means have been omitted from the drawing on account of its very popularity.

Numeral 14 represents a conventional cannon wheel which is rotatable around a conventional cannon pinion 21, the said pinion being arranged concentrically at the center of the movement. A driving gear 14a is rigidly mounted on the cannon wheel 14.

A day calendar dial 15 has a conventional general outside configuration, although only partially shown, and is formed concentrically with a day star wheel 15a by a press-forming job from a sheet stock. The dial 15 comprises a peripheral and concentric plate portion 15b surrounding the central day star wheel portion 15a, said both portions extending in respective horizontal planes of different heights as measured from the surface of pillar plate 1 and being connected rigidly by means of vertically extending connecting portions 150. Regular day representations, Monday, Tuesday are represented on the plate portion 15b, although not shown. A central and resilient ring portion 15d situated at the same height as the plate portion 15b is formed at its inside peripheral surface with inner projections 15e which are kept in engagement with a ring groove 14b on cannon wheel 14 for positioning of the day dial 15 at its predetermined height relative to the cannon wheel.

Numeral 16 represents a positioning plate of substantial outer configuration, only partially shown, said plate 16 being fixedly mounted on the pillar plate by means of set screws as at 22 and 23. The plate 16 acts as a stop for the prevention of an unintentional and excess axial escapement of the dial 13. In addition, the plate 16 is formed with a date jumper lever 16a and a day jumper lever 16b which cooperate with respective calendar dials l3 and 15, as will be more fully described hereinafter.

A date drive wheel 17 is formed at its center with a shaft 17d which is rotatably mounted in a correspondingly shaped bearing opening, not shown, formed in the pillar plate 1. This wheel 17 is a kind of gear which meshes with a gear element 14a rigidly mounted on the cannon wheel 14, so as to make a complete revolution per day, and in counter clockwise direction when seen in FIG. 1. In addition, the wheel 17 is formed with a radially extending resilient pawl 17a which takes a longer one of the gear teeth. A resilient arm 17b is formed on the wheel 17, so as to provide a day drive pawl which has a shouldered tip end.

A pin is formed rigidly on the pawl 17a and adapted for contacting two separated cam elements 16c on positioning plate 16 while the date driving wheel 17 rotates.

Numeral 18 represents a correction member which constitutes a main constituent of the calendar correction mechanism, said member representing a base portion 18a which is rotatably attached to a convenient stationary member of the timepiece movement, preferably said positioning plate 16 as shown, by means of any suitable conventional fixing means such as a riveted pivot 16d as shown. The correction member 18 comprises further a date correction pawl 18b adapted for engagement with feeding teeth 13a of date dial 13 for feeding thereof in case of a date correcting manipulation; a day correction pawl 18c adapted for engagement with day star wheel 15a in case of a day correcting manipulation; a resilient member 18d urging the correction member 18 for holding it at its neutral position without any engagement with either of dial 13 or 15; and an engageable portion 18e adapted for engagement with correcting teeth 7b on the wheel 7 with the stem 2 positioned at its calendar correcting position occupying one of three selectable positions thereof.

In the present embodiment, the free end of the resilient member 18d is formed substantially into a semicircular shape and embraces resiliently a pin 19 which is fixedly mounted on a certain stationary member of the timepiece, preferably the positioning plate 16. By adopting such arrangement, it is possible to provide a sufficiently weak urging force of the resilient nature to the correction member 18 and by use of a relatively short resilient member 18d occupying a least possible space part of the highly crowded inside space of the timepiece movement, thereby reduces the possibility of an unintentional permanent set of the member 18d in spite of a substantial amount of rotational movement of the correction member 18.

In the present preferred embodiment, the date correcting pawl member 18b has been formed into an elongated resilient arm extending from the base portion 18a of the correction member. It is thereby intended to reduce the frictional resistance as met during engagement of the pawl member with internal teeth 13a in the return stroke of the pawl upon completion of a date dial feed step to a possible minimum.

Numeral 20, FIG. 3, represents partially a regular time-display dial which is formed with a date-display window 20a and a day-display window 20b, through which a viewer can observe the respective calendar representations of service on the respective calendar dials as conventionally. These windows have been omitted from FIG. 1 only for simplicity of the drawing.

The operation of the first embodiment so far shown and described is as follows:

In the case of the regular time-keeping and timedisplay service period of the timepiece movement as well as the calendar correction mechanism according to this invention cooperating therewith, motion is transmitted from the regular gear train, not shown, to cannon pinion 21, thence successively through minute wheel 9, cannon wheel 14 and gear 14a to date drive wheel 17 which acts through the intermediary of the dateand day drive pawls upon the calendar dials 13 and 15, respectively, so as to feed each of them a step per day as conventionally.

The stem 2 is positioned at an innermost pushed-in position corresponding to the barrel spring-winding position when the timepiece movement is operating during its regular time-keeping and time-display service. In this regular position, relative to the calendar-correcting position of the correction mechanism shown in FIGS. 1-3, the stem 2 occupies a position nearer to the center of the movement, and thus nearer to the day star wheel 15a. The setting lever 3 has been moved somewhat counter-clockwise from the position shown in FIG. 1 so that the projection 3d is kept in engagement with the outer recess on setting lever spring 6. In this case, the clutch lever 5 is brought into engagement with projections 3b and 3c on setting lever 3 at somewhat outwardly shifted points of the wavy portion 5b in FIG. 1. The correction wheel 7 is positioned at a slightly upward position relative to that shown in FIG. 1 under the influence'of clutch lever 5 kept in engagement with the ring groove 7d on the wheel 7, so as to bring the first gear 7a into meshing with crown wheel 12. Therefore, the correction teeth 7b on the wheel 7 and the engageable portion 18e on correction pawl member 18 are out of engagement with each other.

When an operator now turns the stem 2 under this winding position thereof, motion will be transmitted therefrom through correction wheel 7 to crown wheel 12, thence to a winding wheel, not shown, so as to wind the barrel spring, not shown.

When it is desired to correct calendar representations, the operator must pull out manually the stem 2 upwards in FIG. 1 by one step, so as to bring it to its calendar correcting position. Then, setting lever 3 is turned correspondingly clockwise in FIG. 1, so as to bring the projection 3d into engagement with recess b on the member 6. Then, clutch lever 5 is brought into engagement with projections 3b; 30 on setting lever 3 as shown in FIG. 1, and correction teeth 7b on wheel 7 are brought into the engageable portion 18s on the member 18, thereby the wheel 7 being shifted to its correction service position where it is kept in separation from crown wheel 12 and setting wheel 8. Therefore, all the related parts occupy their respective positions shown in FIGS. 1 and 3.

When the stem 2 is turned in the direction shown by a small arrow A shown in FIG. 1, correction wheel 7 is also turned in the same direction A and the correction teeth 7b entrains the engageable portion 182 on correction pawl member 18 by contacting therewith, thereby the pawl member 18 being caused to turn counter-clockwise against the action of resilient arm 18d, as seen by comparison of FIG. 4 with FIG. 1. The inside teeth 13a of date dial 13 occupied in FIG. 1 are shown by imaginary lines in FIG. 4 for easy comparison. This is applicable to the correction pawl member 18. In this way, the date dial 13 is fed substantially one step by the pawl member 18b from the imaginary position to the full line position in FIG. 4, and the jumper lever 16a will act upon the same dial for performing the remaining feed part, so as to complete the feeding step.

The tip end of the engageable portion 18s of correction pawl member 18 is then released from engagement with correction teeth 7b, as shown in FIG. 4, and then, the related parts will recover their mutual position at the initial stage shown in FIG. 1 under the influence of the action of resilient member 18d. By continuing the turning movement of stem 2 in the direction A, the correction member 18 will repeat the said oscillating motion, thereby the date dial 13 being fed in successive similar steps.

With the reversed rotation of stem 2 in the direction B shown in FIG. 1, correction wheel 7 will follow up the reversed rotation in unison. Thus, correction teeth 7b will accompany the engageable portion 18a of correction pawl member 18 and turn in the clockwise direction as seen from FIG. 5 against the action of resilient arm 18d, thereby the day correction pawl member feeding the day star wheel 15a from its chain-dotted line to its full line position in FIG. 5 and then, the remaining feed is carried out by the action of day jumper lever 16b, so as to complete a feeding step. The essential part of this one step feed executed by the pawl part 180 may be clearly understood by comparing the chaindotted line position with the full line position of the day calendar dial 15 in FIG. 5. At this stage, the engageable portion 18e is released from engagement with the correction teeth, and correction pawl member 18 will return back again to its original position shown in FIG. 1 under the action of resilient member 18d. By continued rotation of stem 2 in the direction B, the day calendar correction can repeatedly progress as before.

In the present first embodiment of the invention, the time-setting operation can be executed asfollows:

By drawing out the stem by a further step upwards from the position shown in FIGS. 1 and 3, setting lever 3 is rotated clockwise and the projection 3d will be brought into engagement with the recess a on setting lever spring 6. Then, the clutch lever 5 is further shifted downwards by the action of projections 3b; 3c, and the third gear 70 of correction wheel 7 is brought into engagement with setting wheel 8, while correction pawl member 18 is released from engagement with second gear 7b. With rotation of stem 2 under these conditions, rotation is transmitted therefrom through correction wheel 7 and setting wheel 8 to minute wheel 9, thus performing a time setting job as required.

As seen clearly from the foregoing, a setting mechanism adapted for performing a selective multi-stage axial positioning operation for the stem 2 is constituted by the combination of setting lever 2, clutch lever 5, stem position 6 and the like. It is not absolutely necessary to design and arrange such a setting mechanism in the manner that a wheel carrying correction teeth is shifted to and fro along the stem 2. It would be thus possible to design and arrange the setting mechanism in such a way that rotation is transmitted in response to the degree of axial drawing-out of the stem to either the correction teeth or the correction pawl member and interrupt the torque transmission. The correction wheel 7 in the meaning of the present embodiment can naturally perform all the necessary manipulation jobs including barrel spring-winding, calendar correction and time-setting. It can be seen further from the foregoing that the correction wheel can be defined as a suitable member provided at least with the correction teeth.

Next, referring to FIG. 6, a preferred second embodiment of the invention will be described in detail. In the present embodiment, same or similar constituent parts are shown by respective same reference numerals as before, yet being added each with 100, for quicker and more comparison and identification.

In the present embodiment, the setting mechanism can be equal to that used in the foregoing first embodiment and thus, has been omitted from the drawing for avoiding superfluous duplication. In FIG. 6, such arrangement is shown that the stem 102 occupies its service position adapted for performing date and day corrections. Numeral 107 represents a correction wheel designed and arranged in the similar way as before. In the position shown in FIG. 6, the engageable portion 1 186 of correction pawl member 118 is kept in engagement with correction teeth 107b.

A substantial difference between the first and second embodiments resides in that the day representations are expressed in two different, yet corresponding languages, although not specifically shown, and that the operator can select any one of these day displays.

For this purpose, seven toothed day star wheel 115a is arranged to cooperate with a day jumper lever 1116b provided with two successive tooth projections 116d and 116e. By adopting this measure, the day star wheel 115a can be positioned in a stabilized manner at two different operational positions shown in full line and in imaginary line in FIG. 6. The day representations expressed in two different languages are given in a closely neighboring manner for each step or tooth pitch. It is necessary to perform mechanically the feed of the star wheel by means of the mechanism, the wheel 115a must be fed once by a complete tooth pitch.

Numeral 117 represents a date drive wheel which is provided with a date drive pawl member 117a and a day drive pawl member ll7b. The first pawl member 117a is formed into a curved and resilient spring strip carrying at its tip end a somewhat longer and thickened tooth portion 1170'. The second drive pawl member 11712 is formed again into a curved resilient strip which is arranged substantially in a rotational symmetry to the first pawl member 1 17a relative to the rotational center of drive wheel 117 and carries at its tip end a thickened, substantially trapezoidal tooth 117b which has a tapered thickness when seen from left to right in FIG. 6. This design will allow to perform an escapement of the resilient strip by deflecting resiliently downwards in the case of reversed rotation of the wheel 1 17 or at the time of calendar correction job performed by the day star wheel a. Date drive pawl member 117a can perform an escapement movement by deflecting inwardly. This resilient escapement feature can be performed equally in the case of the first embodiment, although such description has been omitted therein.

Date drive wheel 117 is provided with a shaft on which a day drive wheel 151 is rotatably and eccentrically mounted. Date drive wheel 117 is arranged to rotate counter-clockwise in FIG. 6 at a complete revolution per day, and the day drive wheel 151 is thereby rotatingly fed by two tooth pitches through the action of day drive pawl 117b. In this way, day star wheel 115a is fed always one tooth pitch through the action of the wheel 151, regardless of the jumpered position of day star wheel 115a either at its imaginary line position or at its full line one shown in FIG. 6. Shaft 150 is mounted on pillar plate 1.

In case of the day-date calendar correction mechanism according to the present second embodiment, it is required not only to correct the position of day star wheel 115a but also to provide a possibility for positioning thereof at every half-pitch staggered position. Therefore, it can be seen that day star wheel 1 15a must be fed stepwise by the half tooth pitch.

Correction pawl member 118 has a similar structure as that of the foregoing member 18 adopted in the first embodiment. More specifically, it comprises a base portion 118a, a date-correcting pawl portion 1l8b and an elastic or resilient portion 118d. An engageable portion 118e thereof is formed with two separated pawls 1 18f and 118g, so as to enlarge the range of the oscillatingly active movement of the member 118. A stud pin 152 is fixedly mounted on the member 118 at its base portion 118a and a day correction member 1180 is mounted frictionally rotatably on said stud pin 152. The member 1186 is provided with two separate projections 153a and 153b, and further with a cam surface 1530 which is so designed and arranged as to make a sliding contact with a stationary guide pin 154 studded on pillar plate 101.

When the stem 102 is rotated in the direction of a small arrow 0, the correction pawl member 118 is rotated in clockwise direction in FIG. 6 by virtue of engagement thereof with gear 107b". Then, the respective tip ends of projections 153a and l53b will describe 8-figured passages as shown in FIG. 6 by two series of small arrows attached thereto, by virtue of the sliding contact of cam surface 1530 with guide pin 154 and by the engagement of the pawl member l with day star wheel 1150.

With the day star wheel 1 15a positioned at its full line position, the projection 153a will shift the wheel to its imaginary lined position. On the contrary, when the star wheel 115a is held at its imaginary lined position, the other projection 153b will shift the star wheel to its full line position.

By continuing the manual rotation of stem 102, day star wheel 115a will be further fed in a progressively stepping mode, each time by a half tooth pitch.

The number of correction teeth 7b or l07b' on correction wheel 7 or 107 can be freely selected, so far as an automatic and resilient return movement of the correction pawl member 18 or 118 by the action of resilient portion 18d or 18d can not be disturbed upon execution of sufficient active rotational movement of the member 18 or 118, respectively. As an example, the number of correction teeth 7b or 107b amounts to 3 in the foregoing embodiments. In this case, a complete revolution of stem 2 or 102, a day and date calendar correction can be performed for three days.

We have found by our practical experiments that if the correction pawl portion is mounted frictionally rotatably on the base portion of the correction pawl member, as shown and described hereinbefore in the second example, the correctingly rotational direction can be selected freely in either direction, even if the relative arrangement of correction pawl member, date calendar dial and day calendar dial be maintained substantially as before.

It should be stressed at this stage that the present invention can be applied not only to the dayand date calendar correction, but also to the correction mechanism of a year calendar representing 12 months, or other similar calendar timepiece mechanisms for performing necessary corrections substantially shown and described hereinbefore.

As may be seen from the foregoing description, the following several advantages can be attained by the present invention By rotation of the manipulating stem, preferably in the form of the winding stem, to-and-fro, selective correction either of the dateor day calendar display can be performed in a simple and easy way, depending upon the selected rotational direction of the stem, thus the calendar correction job being highly convenient for the manipulating operator.

Although the conventional calendar correction mechanism for a timepiece has necessarily two clutch wheels, various and numerous transmission wheels, larger idle wheels and the like, the inventive correction mechanism comprises as its main working constituents a correction wheel mounted on the manipulatable stem, preferably the winding stem, and pivotable correction pawl means, thus representing a possible minimum number of the necessary parts of relatively simple design.

It is also possible according to this invention, if necessary, to fit correction teeth to a conventional winding pinion or clutch wheel which is mounted on the winding stem, and indeed, without provision of a separate correction wheel positioned at a certain other place than the stem, for attaining the aforementioned kind of calendar correction job, the whole mechanism may be still further simplified.

The correction teeth on the correction wheel means can be formed by relying upon the simplest possible mechanical working mode such as the press-forming job, thus the manufacturing costs being reduced to a minimum.

The correction pawl member employable in the present invention can be prepared by relying upon a simple and easy mechanical working technique such as the pressing and bending job, thus the working of the correction pawl member being carried out in a highly simplified and economical way, which contributes to further reducing the manufacturing costs of the calendar correction mechanism, in addition to the highly reduced number of the main working parts of the mechanism adapted for reducing further the manufacturing costs.

Although only the correction pawl member must occupy somewhat larger space than that for the corresponding conventional part, since it is necessary in the case of present invention, the member must cooperate simultaneously with the date dial, day star wheel and correction wheel, and all other main working parts of the mechanism according to this invention are realized by adding only two or so additional elements to the oldfasioned correction mechanism in which only the quick-dayand date calendar corrections are performed through the regular time-setting operation.

Finally, it should be mentioned that why the date drive pawl member 17a and day drive pawl member 17b are formed into an elongated resilient arm, respectively, is such that in the case of occasional reverse rotation of the wheel 17 at the stage of time-setting operation, and even during the stage of calendar dial display correcting operation by use of the inventive correction mechanism, a disadvantageous disturbing toggle phenomenon is thereby effectively prevented. In such disturbinf case inviting such toggling action, the pawl 17a can escape by resiliently flexing towards the rotational center of the wheel 17. In the case of the day drive pawl 17b, it flexed below the drawing paper for making the desired escapement.

The embodiments of the invention in which an exclusive property or privilege is claimed are as follows:

1. Calendar display correction mechanism for a calendar watch with at least two series of calendar representations, comprising a mechanism for setting a manually operable time-setting stem at a plurality of set positions along the longitudinal axis thereof, one of said set positions being destined for the calendar display correction; a correction wheel mounted on said stem for unitary rotation therewith; and a correction pawl member rotatably mounted on a stationary member, preferably a pillar plate, of said timepiece, said pawl member comprising an engageable portion adapted for engagement with said correction wheel, two correction pawl elements cooperating with two calendar display means of the timepiece, and a resilient portion adapted for maintaining said two pawl elements at their neutral and off-service position, said correction pawl member prefonning a pivotal movement by rotational movement of said stem set at its correction service position, one of said pawl elements being adapted for driving one of said calendar display means by rotation of said stem in one direction and the other of said pawl elements being adapted for driving the other of said calendar display means by rotation of said stem in the opposite direction.

2. Calendar display correction mechanism as set forth in claim 1, wherein one of said pawl elements is frictionally rotatably mounted on the base portion of said correction pawl member and provided with a cam surface adapted for cooperation with a guide pin fixedly mounted on a stationary member of the timepiece.

3. Calendar display correction mechanism as set forth in claim 1, wherein the end of said resilient portionof said pawl member is shaped into a curved part embracing a pin fixedly positioned on a stationary member of the timepiece.

4. Calendar display correction mechanism as set forth in claim 3 wherein one of calendar display means is a day calendar display dial, having two series of corresponding day representations expressed in two different languages and the corresponding correction pawl element is provided with two actuating ends adapted for selectingly display of either one of said two series of day calendar representations.

5. Calendar display correction mechanism as set forth in claim 1, wherein the main working part of said correction wheel is a radial gear and the working part of said correcting pawl member is a kind of hook having its working portion extending in a radial plane relative to said stem.

6. Calendar display correction mechanism as set forth in claim 5, wherein said correction pawl member is made from a metallic sheet stock.

7. Calendar display correction mechanism as set forth in claim 6; wherein one of the calendar display means is formed into a date calendar dial ring having a series of inside teeth, characterized by that said correction pawl member is formed with a date correction pawl which comprises a base portion and an elongated resilient aim extending therefrom. 

1. Calendar display correction mechanism for a calendar watch with at least two series of calendar representations, comprising a mechanism for setting a manually operable time-setting stem at a plurality of set positions along the longitudinal axis thereof, one of said set positions being destined for the calendar display correction; a correction wheel mounted on said stem for unitary rotation therewith; and a correction pawl member rotatably mounted on a stationary member, preferably a pillar plate, of said timepiece, said pawl member comprising an engageable portion adapted for engagement with said correction wheel, two correction pawl elements cooperating with two calendar display means of the timepiece, and a resilient portion adapted for maintaining said two pawl elements at their neutral and off-service position, said correction pawl member preforming a pivotal movement by rotational movement of said stem set at its correction service position, one of said pawl elements being adapted for driving one of said calendar display means bY rotation of said stem in one direction and the other of said pawl elements being adapted for driving the other of said calendar display means by rotation of said stem in the opposite direction.
 2. Calendar display correction mechanism as set forth in claim 1, wherein one of said pawl elements is frictionally rotatably mounted on the base portion of said correction pawl member and provided with a cam surface adapted for cooperation with a guide pin fixedly mounted on a stationary member of the timepiece.
 3. Calendar display correction mechanism as set forth in claim 1, wherein the end of said resilient portion of said pawl member is shaped into a curved part embracing a pin fixedly positioned on a stationary member of the timepiece.
 4. Calendar display correction mechanism as set forth in claim 3 wherein one of calendar display means is a day calendar display dial, having two series of corresponding day representations expressed in two different languages and the corresponding correction pawl element is provided with two actuating ends adapted for selectingly display of either one of said two series of day calendar representations.
 5. Calendar display correction mechanism as set forth in claim 1, wherein the main working part of said correction wheel is a radial gear and the working part of said correcting pawl member is a kind of hook having its working portion extending in a radial plane relative to said stem.
 6. Calendar display correction mechanism as set forth in claim 5, wherein said correction pawl member is made from a metallic sheet stock.
 7. Calendar display correction mechanism as set forth in claim 6, wherein one of the calendar display means is formed into a date calendar dial ring having a series of inside teeth, characterized by that said correction pawl member is formed with a date correction pawl which comprises a base portion and an elongated resilient arm extending therefrom. 